Stem Cells from Surgery Leftovers Could Repair Damaged Hearts

Stem cells from leftover sections of vein removed for coronary artery bypass graft (CABG) surgery could stimulate new blood vessels to grow, potentially helping repair damaged heart muscle after a myocardial infarction (MI).

Researchers at the Bristol Heart Institute (BHI) at the University of Bristol (United Kingdom) localized and investigated the presence, antigenic profile, expansion capacity, and proangiogenic potential of CD34-positive progenitor cells from the saphenous vein of patients undergoing CABG. After dissection of the vein from surrounding tissues and enzymatic digestion, the CD34 cells were isolated by selective culture, immunomagnetic beads, or fluorescence-assisted cell sorting. In the presence of serum, the cells gave rise to a highly proliferative cell population that expressed pericyte and mesenchymal antigens, and showed both clonogenic and multilineage differentiation capacities.

The researchers named this cell population saphenous vein-derived progenitor cells (SVPs). In culture, the SVPs integrated into networks formed by endothelial cells, and supported angiogenesis through paracrine mechanisms. Reciprocally, endothelial cell-released factors facilitated SVP migration. Intramuscular injection of SVPs in ischemic limbs of immune-deficient mice improved new vascularization, as well as blood flow recovery. At 14 days after transplantation, proliferating SVPs were still detectable in the recipient muscles, where they established physical contact with the capillary endothelium. The study was published in the April 20, 2010, issue of Circulation.

"This is the first time that anyone has been able to extract stem cells from sections of vein left over from heart bypass operations. These cells might make it possible for a person having a bypass to also receive a heart treatment using their body's own stem cells,” said lead author Paolo Madeddu, M.D., a professor of experimental cardiovascular medicine. "We can also multiply these cells in the lab to make millions more stem cells, which could potentially be stored in a bank and used to treat thousands of patients.”

While non-bone-marrow progenitor cells with proangiogenic capacities are known, they remain clinically unexploited owing to their scarcity, difficulty of access, and low ex vivo expansibility.

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Bristol Heart Institute
University of Bristol